In a prosecution for any alleged violation of a provision of this chapter, if the lack of consent of the victim is an element of the provision that allegedly was violated, evidence that, at the time of the alleged violation, the victim lacked the capacity to give consent is admissible to show that the victim did not give consent.
As used in this section, "lacks the capacity to consent" means being impaired for any reason to the extent that the person lacks sufficient understanding or capacity to make and carry out reasonable decisions concerning the person or the person's resources.